Fix crash in remoteDispatchDomainMemoryStats (CVE-2013-4296)

The 'stats' variable was not initialized to NULL, so if some
early validation of the RPC call fails, it is possible to jump
to the 'cleanup' label and VIR_FREE an uninitialized pointer.
This is a security flaw, since the API can be called from a
readonly connection which can trigger the validation checks.

This was introduced in release v0.9.1 onwards by

  commit 158ba873
  Author: Daniel P. Berrange <berrange@redhat.com>
  Date:   Wed Apr 13 16:21:35 2011 +0100

    Merge all returns paths from dispatcher into single path
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
(cherry picked from commit e7f400a1)

Conflicts:
	daemon/remote.c - context

daemon/remote.c

@@ -1127,7 +1127,7 @@ remoteDispatchDomainMemoryStats(virNetServerPtr server ATTRIBUTE_UNUSED,
                                 remote_domain_memory_stats_ret *ret)
 {
     virDomainPtr dom = NULL;
-    struct _virDomainMemoryStat *stats;
+    struct _virDomainMemoryStat *stats = NULL;
     int nr_stats, i;
     int rv = -1;
     struct daemonClientPrivate *priv =